Fig. 1. InGaAs/GaAs quantum well structure with indium-rich islands.

Fig. 2. Principle of the loss measurement based on the PL spectra from dual facets of an edge-emitting device.

Fig. 3. (Color online) PL spectra measured at the dual facets of the sample pumped by a fiber-coupled 808 nm laser.

Fig. 4. Model of the energy band structure consisting of In0.12Ga0.88As and In0.17Ga0.83As materials.

Fig. 5. Optical loss spectra of the hybrid In0.12Ga0.88As and In0.17Ga0.83As material system.

Fig. 6. (Color online) (a) PL spectra in TE polarization, (b) PL spectra in TM polarization, (c) the whole loss spectrum in TE polarization, and (d) the whole loss spectrum in TM polarization.

Fig. 7. PL spectra in TE and TM polarizations from the gain measurement sample, where the optical pump-induced carrier density is 4.8×1017  cm−3.

Fig. 8. (Color online) Model gains in TE and TM polarizations under different carrier densities of 3.6×1017  cm−3 (black), 4.2×1017  cm−3 (green), 4.5×1017  cm−3 (blue), and 4.8×1017  cm−3 (red).